JPS598306A - Rotary transformer - Google Patents

Abstract

PURPOSE:To reduce a crosstalk among a plurality of channels by constituting magnetic materials by sintered ferrite of high permeability and constituting a nonmagnetic material for shielding interposed among the magnetic materials by nonmagnetic sintered ferrite. CONSTITUTION:A fitting hole 6 for a shaft is formed to a rotor 1 and a fitting hole 7 for a supporter to a stator 2. The rotor 1 contains a disk 3 consisting of a sintered body of ferrite powder, which is nonmagnetic at least working temperature (the normal temperature or more), one part of the disk has an annular projecting section 8, and the projecting section fills the role of the shielding of nonmagnetism. Two annular high-permeability ferrite sintered bodies 41, 42 are united and attached to the surface of a substrate 3, and windings 91, 92 are coupled with the surfaces of these ferrite sintered bodies. The stator 2 is also constituted similarly by a nonmagnetic disk 11 with an annular projecting section 10, annular magnetic ferrite sintered bodies 121, 122 on the surface of the disk, and windings 131, 132 coupled with the surfaces of the sintered bodies.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a p-tally transformer, and more particularly to a rotary transformer that reduces crosstalk between numerical channels.

Rotary transformers are widely used to send and receive signals between circuits that have a rotating part and a stationary part, such as between a sensor attached to a rotating body and a stationary circuit, or between a rotating head and a video recorder. It is used for signal transmission between stationary amplifier circuits, control, measurement, recording and playback, etc. When using a plurality of sensors in such a four-tally transformer, it is necessary to apply windings corresponding to these numbers to the rotor and stator, respectively, to create electromagnetic coupling between the corresponding pairs. .

Since the rotor and stator are generally made of a magnetic material with high magnetic permeability, in conventional rotary transformers, magnetic flux linkage between adjacent channels is unavoidable, resulting in a four-way stalk. The inventors of the present invention have recently proposed to prevent crosstalk by dividing and rearranging the magnetic material for each channel and filling the space with a nonmagnetic material. However, according to this method, it is not possible to provide a rotor or stator with high integrity and high mechanical strength.

The present invention solves the above problem by constructing the magnetic body from sintered ferrite with high magnetic permeability, and by constructing the non-magnetic shielding material interposed between them from sintered ferrite which is non-magnetic at the operating temperature. do. According to the present invention, a kneaded product of non-magnetic and magnetic ferrite powders is molded, they are temporarily bonded, and then fired together to form a mutually integrated sintered body. A rotary transformer consisting of a rotor and a stator can be provided without problems of cracking or distortion due to differential shrinkage, and without problems with the mechanical strength of the finished product.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the present invention, the non-magnetic material is selected from ferrites that are substantially non-magnetic at the operating temperature (represented by MO-F e t Os, where M is a metal), and strictly speaking, It can be a type of magnetic material.

FIG. 1 shows the humidity dependence of the magnetic permeability of two types of ferrites, A is a non-magnetic ferrite F that can be used in the present invention, and B is a normal ferrite. 7) A has high magnetic permeability at low temperatures, but has very low magnetic permeability at around room temperature or higher temperatures.

For example, by selecting the mixing ratio of metals in Cti-Zn ferrite, it is possible to obtain a Cti-Zn ferrite that is non-magnetic at room temperature or has a high magnetic permeability.

FIG. 2 is a sectional view of a disc-shaped four-tally transformer according to a first embodiment of the present invention. The rotor 1 and stator 2 have substantially the same configuration. A mounting hole 6 for a rotating shaft is formed in the row and bottom 1, and a mounting hole 7 for a support body is formed in the stator 2. The fourth part 1 includes a disk 3 made of a sintered body of ferrite powder that is non-magnetic at at least the operating temperature (above room temperature),
A part of it has an annular projection 8, which serves as a non-magnetic shield. Two annular high magnetic permeability ferrite sintered bodies 4 are placed on the surface of the substrate 3. ．． 4. are bonded together, and a winding 9. is further bonded to the surface of these ferrite sintered bodies. ．． 9. are combined. Similarly, the stator 2 includes a non-magnetic disk 11 having an annular protrusion 10, an annular magnetic ferrite sintered body 12 on the surface thereof. ．． 12! , and the volumes bonded to the surface of these sintered bodies are kneaded with an appropriate binder and water, molded in respective predetermined molds, and then bonded and pressed into the shape shown in Figure 2. By firing at a high temperature, the non-magnetic disc 3 and the magnetic material 4□, 4. It can be manufactured by making it into an integral sintered body. Winding 91.91 is A g %Ag-Pd, Pd
It is possible to print a spiral pattern on the surface of the magnetic body 414 using a paste on metal powder such as the above, and then bake it. Alternatively, a similar printing may be performed before firing the sintered body, and the entire body may be fired together. Alternatively, an insulated conductive wire may be bonded to the surface of the magnetic body 41.4 with an adhesive. The production of the stator 2 can be carried out in a similar manner.

FIG. 3 shows a coaxial rotary transformer according to a second embodiment of the present invention. The rotor 14 is an annular body,
The stator 15 is coaxially arranged close to the inner peripheral surface of the rotor 14. The rotor 14 is rotatably supported by bearing means (not shown), for example, on a shaft fixed in a hole 17 of the stator.

The rotor 14 consists of a magnetic annular ferrite sintered body i 81 s 18* that takes charge of each channel, and a ferrite ring 19 that is non-magnetic at least at the working temperature and separates them. A circumferential groove is cut in the inner circumferential surface of the coil, and the winding wires 201120t are fixed therein. Similarly, the stator 15 also includes a magnetic annular ferrite sintered body 21, 1211, a non-magnetic ferrite sintered body ring 22, and a sintered body 21. ．． 21. The windings 1i125. ．． 23. It is composed of The manufacturing method of the rotary transformer of this example is also the same as that of the first example, and magnetic and non-magnetic ferrite are sintered together.

Because of the structure described above, the sintered body of the same type of spinel crystal structure is not only hardly affected by thermal contraction and thermal distortion, but also strongly bonded to each other, resulting in a rotor and stator with excellent mechanical properties. can be obtained. Moreover, since the non-magnetic part separates the magnetic part, the shielding between channels is complete and crosstalk is reduced.

It will be apparent to those skilled in the art that many variations are possible within the scope of the invention. For example, in the example shown in FIG. 2, it is also possible to leave only the non-magnetic protrusions and replace the non-magnetic disk with another ceramic disk or a non-magnetic metal plate. Also the fifth
In the example shown, the magnetic material is 1.81.18! Winding wire 231
．． 23. Winding can be easily performed by stacking elementary elements divided along a horizontal plane passing through the wire.

[Brief explanation of drawings]

? Figure A1 is a graph showing the temperature dependence of magnetic permeability of the non-magnetic material used in the present invention, Figure 2 is a longitudinal cross-sectional view of the rotary transformer of the first embodiment of the present invention, and Figure 3 is a graph showing the temperature dependence of the magnetic permeability of the non-magnetic material used in the present invention. 2
FIG. 3 is a longitudinal cross-sectional view of a rotary transformer according to an embodiment. The main parts in the figure are as follows. 1: Rotor 2: Stator 5. 11: Non-magnetic ferrite disk 8. 9: Non-magnetic 7 elements) II-shaped projections 4, . 4. :Magnetic ferrite 91% 92.151.132' Winding 14: Stomach -
Stator 15: Stator 1B, , 18. ．． 21. ．． 21. :Magnetic ferrite 1
9.22: Non-magnetic ring

Claims (1)

[Claims] +l) A pair of members is prepared in which a number of high permeability magnetic materials corresponding to the number of channels are bonded with a non-magnetic layer interposed therebetween, and a wire is wound on the surface of each of the magnetic materials, and the magnetic materials of both members are In a four-tally transformer whose surfaces face each other and are relatively rotatable, the magnetic material of the number of sleeves is made of ferrite, and the non-magnetic material is made of ferrite, which is substantially non-magnetic at least at the operating temperature. , a four-tally transformer characterized by integrally sintering these.